Last night in town, what should I do?

I'm right next to Union Square - I fly out tomorrow morning. I've done the touristy stuff, so what's left? Not really in the mood to deal with public transport or anything, I've been on one of those "see stuff in SF" buses allllllll day so I'm looking for something easy & close to Union Square.

Absolutely any suggestions are appreciated (other than telling me to fuck off etc, that shit isn't appreciated*)

*Depending on context.